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Effect of Atomic Vacancies on the Structure and the Electrocatalytic Activity of Pt‐rich/C Nanoparticles: A Combined Experimental and Density Functional Theory Study
Author(s) -
Le Bacq Olivier,
Pasturel Alain,
Chattot Raphaël,
Previdello Bruno,
Nelayah Jaysen,
Asset Tristan,
Dubau Laetitia,
Maillard Frédéric
Publication year - 2017
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201601672
Subject(s) - density functional theory , materials science , kirkendall effect , vacancy defect , nanoparticle , atomic units , chemical physics , nanomaterial based catalyst , ab initio , chemistry , nanotechnology , computational chemistry , crystallography , metallurgy , physics , organic chemistry , quantum mechanics
We present a joint experimental and density functional theory (DFT) study on the effect of atomic vacancies on the restructuring of platinum—transition metal alloy nanocatalysts and the associated changes in electrocatalytic activity. Atomic vacancies were introduced into slabs composed of pure Pt monolayers, and the structures were relaxed using the Vienna ab initio simulation package code. Effects of i) the concentration and ii) the spatial distribution of atomic vacancies in the slabs on surface and bulk restructuring were investigated. Highly disordered nanostructures featuring large variations of the in‐plane and out‐of‐plane nearest‐neighbour distances around the mean were observed upon relaxation. These findings were confirmed experimentally by using hollow PtNi/C nanoparticles synthesized by a combination of galvanic replacement and the nanoscale Kirkendall effect (a vacancy‐mediated interdiffusion mechanism). The experimental results also show that hollow PtNi/C nanoparticles feature a combination of oxophilic and oxophobic catalytic sites on their surface and are thus highly active both for electrochemical oxidation and reduction reactions.